I'm sitting in the garden with a glass of wine, looking back through the trees at our railway carriage house for the last time - in its current incarnation, at least. Next time I visit will be the day an enormous crane arrives to hoist the carriages into our neighbours' field so that work can finally begin on the foundations of our eco-house.

This is a moment much longed for and anticipated; delays due to planning problems and a change of architect have left us at least a year behind our original schedule, so I'm enormously excited. I am also, I realise, rather terrified. What if the Victorian carriages are damaged during lifting? What if the money runs out? What if global warming accelerates out of hand and we end up knee-deep in sea water? I worry about the enormous upheavals ahead, not only for ourselves and the carriages, but for our neighbours, the garden, natural surroundings and their inhabitants.

Deep in my heart, though, I know it will be worth it in the end. To build our own home from recycled and renewable materials, and running on solar and biomass energy, is a long-held dream whose day has finally come. As the sun disappears behind the willow tree, I raise my glass to the carriages in a silent toast. It's the end of an era. Here's to the next exciting leg of their journey.

This is my final Green House column. To follow the progress of the project, please visit my blog, Off The Rails, at elspeththompson.co.uk.